| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide iron oxide particles having an excellent particle diameter distribution, excellent magnetic properties, especially excellent coercivity stability, excellent FeO content stability, and excellent heat resistance, and to provide their manufacturing method. <P>SOLUTION: The iron oxide particles contain copper and/or cerium in an amount of 0.001-0.5 wt% based on the total amount of iron oxide particles. The variation of coercivity of powdery toner particles, which are obtained by pulverizing a kneaded material of the iron oxide particles and a thermoplastic resin, is preferably ≤5 Oe at an external magnetic field 10 kOe. Further, when drying the iron oxide, the difference of FeO content between the sample that is dried in vacuum and the sample that is dried in air at 50°C for 12 hours is preferably ≤5 wt%. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
